Contemporary hard disk drives include an actuator assembly pivoting through an actuator pivot to position one or more read-write heads, embedded in sliders over a rotating disk surfaces. The data stored on the rotating disk surface is typically arranged in concentric tracks collectively referred to as the data region. To access the data of a track, a servo controller first positions the read-write head by electrically stimulating the voice coil motor, which couples through the voice coil and an actuator arm to move a head gimbal assembly in positioning the slider close to the track. This process is often referred to as a track seeking process. Once the slider and its embedded read-write head are close to the track a second process known as a track following process takes over the control of positioning the read-write head to access the track.
In the last few years, hard disk drives have begun to incorporate the use of micro-actuators to further control the lateral position of the read-write head during the track following process. These micro-actuators have tended to be a pair of piezoelectric micro-actuators, located on perpendicular sides of the slider to the side closest to the read-write head. The use of dual piezoelectric micro-actuators has been preferred because it increased the stroke sensitivity, or lateral variation delivered to the slider for similar potential differences. The high stroke sensitivity has been required, due to the track pitch of contemporary hard disk drives. While these existing dual piezoelectric micro-actuators work, they are inherently more expensive to build than a micro-actuator involving just one piezoelectric component. What is needed is a single piezoelectric micro-actuator delivering enough stroke sensitivity to meet the requirements for track following in a hard disk drive.